When providing telecommunications services such as voice calls, Short Message Service (SMS), or certain Internet Protocol communications such as Rich Communications Suite (RCS), the desired destination user device is addressed using the mobile station or mobile subscriber number (MSISDN) of the destination user device. However, most territories have a number of different competing mobile network operators who support communications with different user devices. Accordingly, in order to contact the destination user device using the mobile station number and to provide telecommunications services it is necessary to route any communications request to the specific mobile network operator who supports communications with the destination user device, commonly referred to as the specific mobile network operator which owns the mobile station number.
Generally, mobile station numbers are allocated to user devices by a national or regional number authority assigning each of the mobile network operators in a country or region a block or range of mobile station numbers. The mobile network operators then in turn assign each of their customer user devices a mobile station number taken from their respective assigned range. Historically, lists of the assigned ranges of numbers were made available to mobile network operators so that the mobile network operator supporting communications with a specific destination user device could be identified by comparing the mobile station number of the user device with the lists. Communications requests for the destination user device could then be correctly routed to the identified mobile network operator.
However, most telecommunication regulators have now introduced, or are expected to introduce in the future, mobile number portability services allowing users to keep the mobile station numbers of their user devices when they change to a new mobile network operator. As a result, the identity of the mobile network operator supporting communications with the user device using a specific mobile station number may change over time so that the lists of assigned ranges of numbers cannot be relied upon.
In order to provide voice call and SMS telecommunications services a number of approaches have been used to route telecommunications to the correct mobile network operator for a destination user device.
One model for changing operator is for a user to request a new operator to take over responsibility for supporting communications with the mobile number of a user device, and for the new operator to take over full responsibility for the mobile number, referred to as the recipient-led model. When the recipient-led model is used all mobile network operators in a country or region synchronise or combine their number databases so that all mobile network operators are aware which mobile network operator is currently supporting communications with each mobile station number.
Another model for changing mobile network operator is for a user to request authorization from their current mobile network operator to allow their new mobile network operator to use the mobile number of a user device, referred to as the donor-led model. In the donor-led model only the old and new mobile network operators are aware of the change, so that each mobile network operator is only aware of numbers which it has transferred to other mobile network operators or which other mobile network operators have transferred to it. When the donor-led model is used a communications request for a mobile number is made to the original mobile network operator for that number, and the original mobile network operator is responsible for forwarding the communications request to the new mobile network operator.
However, there may be problems in attempting to use these approaches to support Rich Communications Suite (RCS) telecommunications services. Where the recipient-led model is used it may be technically complex, difficult and expensive to combine the number databases of all of the different mobile network operators. Further, even if a combined number database is produced for all mobile network operators in a country or region it may then be complex, difficult and expensive to arrange for mobile networks located outside the country or region to access the combined database. Where the donor-led model is used it is necessary for previous mobile network operators to assist in routing by forwarding RCS communications requests to new mobile network operators, and some mobile network operators may be unable or unwilling to do this. Further, the volume of telecommunications traffic generated by RCS telecommunications services may be much higher than for voice call and SMS services, so that even where this approach is used to deal with number portability for voice call or SMS services it may not be useable for RCS telecommunications services.
A further problem with RCS telecommunications services is that third party operators, also known as over the top providers, who are not themselves mobile network operators may provide RCS telecommunications services to user mobile devices in parallel with the mobile network operator owning the mobile station number of the user mobile device. In this case it can be technically complex, difficult and costly to include the third party operators in addition to the mobile network operators in a common routing solution.
A number of approaches to address the problems of routing when providing RCS telecommunications services have been proposed, but none of these provide a satisfactory routing solution. One proposal is to outsource responsibility for providing RCS routing data to an independent third party provider separate from the mobile network operators. This approach can result in complex and fragmented solutions, and it can be technically complex and demanding to integrate all of the necessary databases.
Another proposal is for a number of mobile network operators to group together and use a common central interconnect hub to provide RCS routing services for telecommunications traffic to and from all of the mobile network operators in the group. This approach can have considerable integration costs, and it may be technically complex and difficult to integrate all of the databases of the different mobile network operators.
Another proposal is for countries using the donor-led model to simply use a similar approach as for voice calls and SMS and make the original mobile network operator responsible for routing RCS telecommunications traffic to the new mobile network operator. This has the problem that routing relies on a mobile network operator who may no longer have any relationship with either of the communicating parties, and who may not be willing, or able, to route RCS telecommunications traffic to the new mobile network operator.
Further, all of these proposals suffer from the technical problem that a mobile network operator is forced to rely on another party for routing information or services, which are a core requirement to provide an acceptable quality of service to users.
Another proposal is for two mobile network operators to be interconnected so that each mobile network operator can forward any unresolved RCS telecommunications traffic, that is any RCS telecommunications traffic for mobile device numbers which are not owned by that mobile network operator, to the other interconnected mobile network operator. This has the problem that a large amount of redundant telecommunications traffic may need to be exchanged between the two mobile network operators, and that this approach cannot be extended to more than two mobile network operators.
The discussion above relates to RCS telecommunications services. However, similar problems will apply to other Internet Protocol communications.
The embodiments described below are not limited to implementations which solve any or all of the disadvantages of the known approaches described above.